From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21A8E17A300 for ; Mon, 20 Apr 2026 15:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776698812; cv=none; b=iRYcA8HeM44f6UaljYAMDRvfAONN+wYMvJHvXhA/HagNNJUs90TYlrtXqtCbBgnmXnH/m89SwIv6kRp8ieKMvTjQ7PrjdYMV1wz/aCv34RPBcYYkVy9oGguYm08RN+exXnMoPFjz7OCDvCm9y9AvF3AdgBUKH3XLNjzGDRZwBjs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776698812; c=relaxed/simple; bh=dATQRFKcNLJjjRyV6a0dyqXpJdGDzEDhkgxOQ+dCuZg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EqdzWdrEtFtimy9nvQ9Z6Zi5yWOeVJeGfBFH0XlxGAaJIvNylnQdVynD/BVjouJu50WUpp0yImLncEYnPjBY63aYjJXYf5q+TRGoGU3ZJcrzdtBDaaOq8/n4nQ3NRgCdx3AjVJuhkBHGeYLysxH+Xh+PLCyHT+6lXKBDPaIdCNA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=APDsAXQA; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="APDsAXQA" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776698807; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hcVVsfBQNN9rrh6Uf5d8BNbIQC5J9iqF/mHK2jES+/k=; b=APDsAXQAq2nsKFhmwG4HRIjCXYyF0ZD4auO7kGWk4rJjrXpxpNEqzfOIXIC0jnnCau2jB5 qGhZBmi72sqOjXuOY5e1nYOSm45HQMGWVuYakK81y1sPWgmBz4d04rPJJKotGQ90LEfQ6V k+VECB6m0H4cFR62U+cstSedjHzfTWc= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-661-ohZyS1s6OyOy4C4sgKJYyw-1; Mon, 20 Apr 2026 11:26:43 -0400 X-MC-Unique: ohZyS1s6OyOy4C4sgKJYyw-1 X-Mimecast-MFC-AGG-ID: ohZyS1s6OyOy4C4sgKJYyw_1776698792 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AD9A8195605E; Mon, 20 Apr 2026 15:26:32 +0000 (UTC) Received: from fedora-work.redhat.com (unknown [10.22.65.236]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 5C7D819560B1; Mon, 20 Apr 2026 15:26:28 +0000 (UTC) From: David Jeffery To: linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich Cc: Tarun Sahu , Pasha Tatashin , =?UTF-8?q?Micha=C5=82=20C=C5=82api=C5=84ski?= , Jordan Richards , Ewan Milne , John Meneghini , "Lombardi, Maurizio" , Stuart Hayes , Laurence Oberman , Bart Van Assche , Bjorn Helgaas , "Martin K . Petersen" , John Garry , David Jeffery Subject: [PATCH 2/5] driver core: do not always lock parent in shutdown Date: Mon, 20 Apr 2026 11:26:05 -0400 Message-ID: <20260420152608.6244-3-djeffery@redhat.com> In-Reply-To: <20260420152608.6244-1-djeffery@redhat.com> References: <20260420152608.6244-1-djeffery@redhat.com> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Don't lock a parent device unless it is needed in device_shutdown. This is in preparation for making device shutdown asynchronous, when it will be needed to allow children of a common parent to shut down simultaneously. And only acquire a reference to the parent device if the parent is to be locked. Signed-off-by: Stuart Hayes Signed-off-by: David Jeffery Tested-by: Laurence Oberman --- drivers/base/core.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 5353c6c22d49..a32fc7141957 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4783,13 +4783,8 @@ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) return error; } -static void shutdown_one_device(struct device *dev) +static void __shutdown_one_device(struct device *dev) { - struct device *parent = dev->parent; - - /* hold lock to avoid race with probe/release */ - if (parent) - device_lock(parent); device_lock(dev); /* Don't allow any more runtime suspends */ @@ -4812,10 +4807,23 @@ static void shutdown_one_device(struct device *dev) } device_unlock(dev); - if (parent) +} + +static void shutdown_one_device(struct device *dev) +{ + struct device *parent; + + /* hold lock if needed to avoid race with probe/release */ + if (dev->bus && dev->bus->need_parent_lock && + (parent = get_device(dev->parent))) { + device_lock(parent); + __shutdown_one_device(dev); device_unlock(parent); + put_device(parent); + } else { + __shutdown_one_device(dev); + } - put_device(parent); put_device(dev); } @@ -4841,12 +4849,6 @@ void device_shutdown(void) dev = list_entry(devices_kset->list.prev, struct device, kobj.entry); - /* - * hold reference count of device's parent to - * prevent it from being freed because parent's - * lock is to be held - */ - get_device(dev->parent); get_device(dev); /* * Make sure the device is off the kset list, in the -- 2.53.0